False ceilings



United States Patent 3,405,489 FALSE CEILINGS Karl Per Frisk, Gamleby, Sweden, assignor to Ernst O. V.

Ekman, Bjorn Brundin, and Carl 0. A. Ekman, partners, trading as Licentia, Ekman & Brundin, Stockholm, Sweden, a Swedish firm Filed Apr. 8, 1966, Ser. No. 541,239 Claims priority, application Sweden, Apr. 12, 1965, 4,744/ 65 1 Claim. (Cl. 52-222) One kind of false ceiling comprises a surrounding frame which is secured to the structure of the room, that is usually to the walls of the room, and a sheet of plastic foil which is held stretched in position within the frame by the engagement of a border of the sheet with the frame.

In accordance with the present invention, in such a ceiling the frame has a longitudinal channel which faces into the room and the lower wall of which is formed with a shoulder facing the base of the channel, and the border is made of a resilient plastic material having in use a U-shaped cross-section with an upper thinner one of the flanges of the U fixed to the edge of the sheet and a lower thicker one of the flanges of the U extending back beneath the sheet; the arrangement being such that the border is held in the channel in the frame by the engagement of the free edge of the thicker flange behind the shoulder and by the tension in the sheet which causes the border to rock in the channel to provide a wedging action as the base of the U bears against the upper wall of the channel.

This arrangement provides a simple and inexpensive fixing between the plastic foil and the frame and enables the ceiling to be erected very quickly. The ceiling may also easily be taken down when for instance repairing electric cables covered by the ceiling or for washing the ceiling. During erection the border of the sheet is forced into the channel by means of a metal blade or similar tool which is pushed into the U of the border beneath the sheet. For dismantling of the ceiling a pointed tool such as an awl or needle may be pressed into the end of the thicker flange to raise it out of engagement with the shoulder of the channel so that the thicker flange of the border at this place may be drawn out of the channel. Starting from this place it will then be easy to raise the thicker flange out of engagement with the shoulder successively along the length of the border and thereby release the border from the shoulder of the channel along the whole frame. For dismantling the ceiling in this manner, the thickness of the free edge of the thicker flange should be greater than the height of the shoulder.

The border may have a substantially constant U-shaped section in it unstressed condition. Alternatively the border may form a substantially flat strip in its unstressed condition with the thinner flange secured to the sheet and the thicker flange forming an extension of the thinner flange. Preferably there is then a creasing line at the junction between the thinner and thicker flanges to facilitate bending of the border into a U-shaped section when the border is pushed into the channel of the frame. In both forms the border when in use in the channel will have a U- shaped section.

Preferably, the thicker flange of the border diverges towards its free edge with a gradually decreasing thickness into the inner flange of the border. A border of this form provides a self compensating effect to support the tension in the foil. Thus when the foil is under a greater tension, it pulls the thinner upper flange of the border further out of the channel and distorts the border section formed by the thinner and thicker flanges so that the thicker flange is wedged even more between the upper and lower walls of the channel and becomes shorter and stubbier and, therefore, of greater bending resistance.

3,405,489 Patented Oct. 15, 1968 An example of a ceiling constructed in accordance with the invention is illustrated in the accompanying drawings, in which:

FIGURE 1 is a vertical section through the frame of the ceiling;

FIGURE 2 is a cross-section of one border for the sheet of plastic foil in its unstressed condition and prior to fixing to the edge of the sheet;

FIGURE 3 is a section similar to FIGURE 2 but showing the border welded to the edge of the sheet;

FIGURE 4 is a cross-section of a second border shown in its unstressed condition in solid lines, and bent into a U-section as shown in dotted lines ready to be pushed into the channel of the frame;

FIGURE 5 is a vertical section through the frame when the border has been placed in position in the channel of the frame by means of a blade indicated by dotted lines; and,

FIGURE 6 is the same section as FIGURE 5 but showing a pointed tool such as an awl inserted into the end of the thicker flange of the border to raise it out of engagement with the shoulder of the channel.

A wooden moulding 1 providing the appearance of a cornice from below is stuck, nailed or otherwise secured to the existing wall 2 andceiling surfaces 3 of a room. The false ceiling proper consists of a sheet of P.V.C or other plastic foil 4 the edges of which are secured to the frame 1 by means of a border as shown in FIGURE 5. The border which is an extrusion of a flexible plastic material has a thinner flange 5 welded to an edge of the sheet and a thicker flange or blocking bar portion 6 which is several times as thick as the flange 5. The thicker flange 6 tapers from its free edge 7 towards the region 8 where it merges into the thinner flange 5. In the modification shown in FIGURE 4 these is a crease line 9 to indicate where the border shall be bent during erection as indicated by dotted lines.

The frame 1 has a horizontal channel facing into the room with an upper flat wall 10 and a lower wall 11. The height H of the mouth of the channel is very slightly greater than the maximum thickness of the border, that is the sum of the maximum thicknesses a and b of the thinner and thicker flanges 5 and 6 respectively and the thickness of the foil. The bottom wall 11 of the channel is formed with a longitudinal recess 12 the front of which provides a rearwardly facing shoulder 13. Alternatively, the bottom of the recess may form the bottom wall behind the shoulder as indicated by dotted lones in FIG- URE 1.

During erection of the ceiling in a rectangular room the frame 1 is first fixed to all four walls of the room and the border is welded to all four edges of the sheet 4. The border at each edge of the sheet in turn is then forced into a corresponding channel, using a tool in the form of a metal blade 14 (FIGURE 5), until the edge 7 engages behind the shoulder 13. The tension in the sheet 4 rocks the border in the channel so that, as shown in FIGURE 5, the flanges of the U spread apart and the border wedges in compression in the channel with the base of the U in contact with the wall 10. To obtain this action the width L of the blocking bar or thicker flange 6 must be greater than the height A between the upper wall 10 and the bottom of the recess 12 and so that the blocking bar will take an oblique position in the channel as shown.

A particular advantage is obtained by a more or less gradual tapering of the border from the edge 7 through the region 8 to the thinner flange 5. This is that when a pull is exerted on the flange 5 by the sheet 4, the rounded outside surface of the region 8 of the U rolls against the upper wall 10 causing a thicker portion ofthe border to form the base region 8 of the U and come into contact with the upper wall 10 of the channel. As a result, the

flange 6, which acts as a blocking bar, will be wedged more tightly between the shoulder 13 and the wall 10.

As will be seen from FIGURES 5 and 6 the height H of the shoulder 13 is less than the thickness b of the free end of the thicker flange 6 so that the exposed end surface of the portion 6 may be reached by a pointed tool such as an awl or needle 15, as shown in FIGURE 6, when the end portion 7 can be raised out of engagement with the shoulder for dismantling the ceiling. This is easily done by bending the needle 15 downwardly in the direction of the arrow 16.

I claim:

1. In a false ceiling supported from the permanent structure of a room and comprising a surrounding frame, means securing said frame to said permanent structure, a sheet of plastic foil, and coupling means adapted to hold the edges of said plastic foil to said frame with said foil stretched within said frame; the improved coupling means which comprises upper and lower wall parts of said frame defining a channel therein facing into said room, a shoulder on said lower wall part facing back into said channel, a resilient plastic border of U-shaped cross-section removably located within said channel and extending around the edge of said sheet, said U including a base, a

first upper thinner flange, and a second lower thicker flange which diverges from said base toward a free edge, means securing said first flange to said edge of said sheet with said base innermost within said channel, and thefree edge of said second flange engaging behind said shoulder whereby said base is held against said upper wall part and said second flange is wedged in said channel in abutment with said shoulder under the tension in said sheet, the thickness of said free edge being greater than the height of said shoulder, whereby said second flange may be disengaged from said shoulder by applying an upward force to said free edge.

References Cited UNITED STATES PATENTS 1,940,637 12/1933 Stubnitz 5353.3 3,177,501 4/1965 Kwake -392 3,186,129 6/1965 Blood 52-222 3,205,628 9/1965 Frisk 52273 FOREIGN PATENTS 986,281 3/1965 Great Britain.

HENRY QSUTHERLAND, Primary Examiner. 

1. IN A FALSE CEILING SUPPORTED FROM THE PERMANENT STRUCTURE OF A ROOM AND COMPRISING A SURROUNDING FRAME, MEANS SECURING SAID FRAME TO SAID PERMANENT STRUCTURE, A SHEET OF PLASTIC FOIL, AND COUPLING MEANS ADAPTED TO HOLD THE EDGES OF SAID PLASTIC FOIL TO SAID FRAME WITH SAID FOIL STRETCHED WITHIN SAID FRAME; THE IMPROVED COUPLING MEANS WHICH COMPRISES UPPER AND LOWER WALL PARTS OF SAID FRAME DEFINING A CHANNEL THEREIN FACING INTO SAID ROOM, A SHOULDER ON SAID LOWER WALL PART FACING BACK INTO SAID CHANNEL, A RESILIENT PLASTIC BORDER OF U-SHAPED CROSS-SECTION REMOVABLY LOCATED WITHIN SAID CHANNEL AND EXTENDING AROUND THE EDGE OF SAID SHEET, SAID U INCLUDING A BASE, A FIRST UPPER THINNER FLANGE, AND A SECOND LOWER THICKER FLANGE WHICH DIVERGES FROM SAID BASE TOWARD A FREE EDGE, MEANS SECURING SAID FIRST FLANGE TO SAID EDGE OF SAID SHEET WITH SAID BASE INNERMOST WITHIN SAID CHANNEL, AND THE FREE EDGE OF SAID SECOND FLANGE ENGAGING BEHIND SAID SHOULDER WHEREBY SAID BASE IS HELD AGAINST SAID UPPER WALL PART AND SAID SECOND FLANGE IS WEDGED IN SAID CHANNEL IN ABUTMENT WITH SAID SHOULDER UNDER THE TENSION IN SAID SHEET, THE THICKNESS OF SAID FREE EDGE BEING GREATER THAN THE HEIGHT OF SAID SHOULDER, WHEREBY SAID SECOND FLANGE MAY BE DISENGAGED FROM SAID SHOULDER BY APPLYING AN UPWARD FORCE TO SAID FREE EDGE. 